Sealing arrangement for eddy current apparatus

ABSTRACT

The hub portions of a field generating means and of an Eddy current developing means form an annular space in which a ball bearing is located. Two sealing rings are provided in the annular space on opposite sides of the ball bearing and form on one side of the same, a storage chamber filled with a lubricating grease for the ball bearing. Each sealing ring is attached to one hub portion and having parallel annular grooves. Stacks of annular metal laminations are respectively located in the grooves, and attached to the other hub portion. The laminations have lateral annular surfaces abutting each other.

United States Patent Hoyler 1 June 6, 1972 [54] SEALING ARRANGEMENT FOREDDY 3,112,417 ll/1963 Tamm ..310/90 CURRENT APPARATUS 2,774,895 12/1956Zuckermann ..3 10/93 [72] Inventor: Alfred Hoyler, Stuttgart, GermanyFOREIGN PATENTS OR APPLICATIONS [73] Assignee: Robert Bosch Gmbll,Stuttgart, Germany 1,094,525 12/1960 Germany ..3 10/90 [22] Filed: on1970 Primary Examiner.l. D. Miller [21] Appl. No.: 85,145 AssistantExaminerR. Skudy AttorneyMichael S. Striker [30] Foreign ApplicationPriority Data 57] ABSTRACT Nov. 3, 1969 Germany .1G 69 42 657.9 The hubportions of a field generating means and of an Eddy current developingmeans form an annular space in which a 2% 310/ 3 1321 27 ball bearing islocated. Two sealing rings are provided in the d 88 105 annular space onopposite sides of the ball bearing and form 1 le 0 308/182] on one sideof the same, a storage chamber filled with a I lubricating grease forthe ball bearing. Each sealing ring is attached to one hub portion andhaving parallel annular [56] Referenm Cned grooves. Stacks of annularmetal laminations are respectively UNITED STATES PATENTS located in thegrooves, and attached to the other hub portion. The laminations havelateral annular surfaces abutting each 3,283,188 11/1966 Edick ..310/l05other. 2,991,514 7/1961 Cotchett... ...308/187.1 3,381,968 5/1968Neilson ..308/l 87.1 8 Claims, 3 Drawing Figures PATENTEDJUH s 1912 3.668,446

SHEET 1 0F 2 INVENTUR. Mme- #W fl PATENTEDJUM 6m 3,668,446

SHEET 2 BF 2 INVENTOR. ALF/2E) H 7 2 BACKGROUND OF THE INVENTION Thepresent invention is concerned with a sealing arrangement, and moreparticularly with a sealing arrangement for an Eddy current brake inwhich two coaxial hub portions form a storage chamber for a lubricatinggrease in which the ball bearing is located.

Eddy current brakes of this type according to the prior art have springbiassed sealing lips bounding the storage chamber which either abut therotor hub or the rotor shaft. During rotation of the rotor at highspeed, friction heat is generated which heats the adjacent bearing partsso that the radial play of the ball bearing is eliminated, resulting indestruction of the bearmg.

In another arrangement of the prior art, the storage chamber. for thelubricating grease is sealed by rings which have adjacent annulargrooves in a cylindrical sealing surface. Sealing rings of this type areintended to produce the effect of a labyrinth seal, but are not capableof preventing the entering of dust and other foreign particles into thebearing.

SUMMARY OF THE INVENTION It is one object of the invention to overcomethe disadvantages of known sealing arrangements for Eddy current brakes,and to provide a sealing arrangement which protects the bearing fromdust and other foreign particles, while developing little friction andconsequent heat.

Another object of the invention is to provide sealing means between arotary part and a stationary part which produce little friction heat.

Another object of the invention is to provide a sealing arrangement fora storage chamber containing a lubricating substance, which isconstructed so that the replacement of the lubricating substance in thestorage chamber can be made at long intervals, so that servicing isimproved and simplified.

Another object of the invention is to provide a sealing arrangementwhich produces a temperature of about 80C lower than the temperatureproduced in similar apparatus by sealing arrangements according to theprior art. I

With these objects in view, an embodiment of the invention, applied toan Eddy current apparatus, comprises field generating first means, andEddy current developing second means, at least one of the same beingrotatable relative to the other, the first and second means having firstand second annular support portions, respectively, forming an annularspace; ball bearing means located in the annular space between the firstand second annular support portions; and two sealingmeans located in theannular space on opposite sides of the ball bearing means and forming atleast on one side of the same, a storage chamber adapted to contain asupply of a lubricating substance for the ball bearing means.

lnaccordance with the invention, each sealing means includes a sealingring attached to one of the annular support portions and having at leastone, and preferably several, annular circumferential grooves, and-atleast one stack of annular laminations attached to the other annularsupport portion and located in the annular groove.

Only low friction developed between the sealing ring and the respectivestack of laminations during relative rotation of the first and secondmeans, particularly when the sealing ring consistsof a thermo insulatingsynthetic plastic material, and the laminations consist of thin metalsheets laterally abutting each other and provided with slits.

A sealing means including a sealing ring with grooves, and stacks oflaminations located in the grooves, is not limited to the use in an Eddycurrent apparatus, but may be used between other rotary and stationaryparts.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its constructions and its methodof operation, together with additional ob jects and advantages thereof,will be best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary axial sectionalview illustrating an embodiment of the invention;

FIG. 2 is a fragmentary sectional view illustrating a sealing meansaccording to the invention on a larger scale; and

FIG. 3 is a fragmentary axial sectional view illustrating anotherembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to theembodiment of FIG. 1, which shows a pole wheel 11 having alternate poles12 and 13 of alternate polarity ending in cylindrical surface portionsand carrying an induction coil 14 which, when energized causes thegeneration of a magnetic field in the region of the poles'12 and 13. Thepole wheel 11 is stationary and mounted on an annular supporting housing22, and is further supported by annular holders 23 at the end of bracingrods.

The periphery of the pole wheel 11 is surrounded by a drum portion 15which has cooling fins 16 and an annular reinforcing member 17, and issecured to the flange 18 of an annular supporting hub portion 19 intowhich a splined end portion 20 of a shaft projects. Shaft 20, which isdriven from a transmission in a housing 21, rotates the hub portion 19with the drum portion 15 so that Eddy currents develop in the drumportion 15 in a manner which is not an object of the invention. Anannular space 24 is formed between the inner cylindrical surface of thepole wheel 11 and the annular hub portion 19. A ball bearing 25 ismounted in this annular space, and has an outer race 26 which is securedbetween the shoulder 27 of the pole wheel 11 and a ring 28 which issecured by a screw to the body of the pole wheel 11. The inner race 30of the ball bearing 25 is clamped between a shoulder 31 of the hubportion 19 and the sleeve 32 by means of a nut 33 screwed onto a threadon the annular supporting hub portion 19.

The annular space 24 between pole wheel 11 and hub portion 19 is sealedon opposite sides of ball bearing 25 by two sealing means. Each sealingmeans includes a sealing ring 35 with two radial outwardly open annulargrooves 36, see FIG. 2, in each of which a stack of four annularlaminations 37 is located with little axial'and radial play. Thelaminations of which each stack 37 consists, are made of hardened steel,and are thin and radially slotted. The lateral planar faces of thelaminations abut each other with or without play, while' the outerperipheral edges of all laminations are fixedly attached to the innersurface of the inner supporting portion of the pole wheel 11, and of theholding ring 28, respectively. The sealing rings 35 are made of asynthetic material, e.g., polyamide filled with glass fibers insulatingagainst the flow of electric and heat currents, and are fixedly attachedto the hub portion 19 and to the sleeve 32, respectively. The outerdiameter of the sealing rings is a little less than the inner diameterof the pole wheel 11 and of the holding ring 28. The sealing means 35,37 form in the annular space between the pole wheel 11 and the hubportion 19, a storage chamber 24 for a lubricating substance which canbe injected into the storage chamber 24 through a conduit 40 in polewheel 11, and through a tube 41 provided with a lubricating nipple 42secured to pole wheel 11. Preferably, a water repellent grease is placedin the annular grooves 36 before the storage chamber 24 is filled with agrease which is suitable for the ball bearing 25.

In the embodiment illustrated in FIG. 3, a stationary ring 50 carriesseveral coils 51 with cores 52 arranged at equal distances parallel tothe axis of the ring 50. In front of the outer ends of cores 52, whichform pole faces, annular means 53, 54 rotate, which are secured by ribs55, 56 to the flange 57 of a hub portion 58. During rotation of themeans 53, 54, Eddy currents are developed in the same due to themagnetic field generated by the coils 51 and cores 52. The stationarymember 50 has a hub portion 58 to which the outer race of a ball bearing59 is secured, while the inner race of the ball bearing abuts the sleeve58c against which it is pressed by a nut 58a on a threaded portion ofhub portion 58. Between the hub portion 500, and the hub portion 58, anannular space is formed in which two sealing devices 35, 37 are locatedfor forming on one side of ball bearing 59, a storage chamber for alubricating substance by which ball bearing 59 is lubricated. A conduit61 with a lubricating nipple 62 is provided in the inner supportingportion 50 a of member 50 so that the storage chamber 60 can be filledwith the lubricating substance, when required. Each sealing meansincludes a sealing ring 58 with grooves 36, and stacks of laminations37, as described in detail with reference to H6. 2.

The storage chamber 60 is preferably filled with the ball bearinggrease, while a water repellent grease is placed in the annular grooves36 before the assembly.

Due to the fact that the sealing means 35, 36, 37 in accordance with theinvention are provided on opposite sides of the ball bearings, no dustcan enter the ball bearings, and due to the construction of each sealingmeans, the friction is low and the adjacent parts are not substantiallyheated during rotation of the rotary means.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofsealing arrangements differing from the types described above.

While the invention has been illustrated and described as embodied insealing means including a grooved sealing ring and stacks of metallaminations located in the grooves of the sealing ring, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowingclaims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. In an Eddy current apparatus, in combination, a sealing arrangementcomprising field generating first means and Eddy current developingsecond means, at least one of said means being rotatable relative to theother, said first and second means having first and second annularsupport portions, respectively, forming an annular space; ball bearingmeans located in said annular space between said first and secondannular support portions; and two sealing means located in said annularspace on opposite sides of said ball bearing means and forming at leaston one side of said ball bearing means, a storage chamber adapted tocontain a supply of a lubricating substance for lubricating said ballbearingmeans, and protected from dust by said sealing means, eachsealing means including a sealing ring attached to one of said annularsupport portions and having at least one circumferential annular groove,and at least one stack of annular laminations attached to the other ofsaid annular support portions and located in said annular groove, saidlaminations having planar annular lateral surfaces abutting each other.

2. Sealing arrangement as claimed in claim 1 comprising lubricatingmeans on one of said first and second means opening into said storagechamber for supplying the lubricating substance into the same.

3. Sealing arrangement as claimed in claim 1 wherein said laminationsconsist of hardened steel.

4. Sealing arrangement as claimed in claim 1 wherein said laminationshave slits.

5. Sealing arrangement as claimed in claim 1 wherein said sealing ringsconsist of a material insulating against the flow of electric and heatcurrents. h

6. Sealing arrangement as claimed in claim 1 wherein said fieldgenerating first means is stationary, and said Eddy current developingsecond means is rotatable about an axis; wherein said laminations engageand are attached to said first annular support portion of said firststationary means; and wherein said sealing rings engage and are attachedto said second annular support portions of said second rotatable means.

7. Sealing arrangement as claimed in claim 1 wherein each sealing ringhas a plurality of parallel circumferential annular grooves; and whereina stack of annular laminations is located in each annular groove.

8. Sealing arrangement as claimed in claim 4 comprising a waterrepelling grease in said annular grooves; and a ball bearing grease insaid storage chamber.

1. In an Eddy current apparatus, in combination, a sealing arrangementcomprising field generating first means and Eddy current developingsecond means, at least one of saId means being rotatable relative to theother, said first and second means having first and second annularsupport portions, respectively, forming an annular space; ball bearingmeans located in said annular space between said first and secondannular support portions; and two sealing means located in said annularspace on opposite sides of said ball bearing means and forming at leaston one side of said ball bearing means, a storage chamber adapted tocontain a supply of a lubricating substance for lubricating said ballbearingmeans, and protected from dust by said sealing means, eachsealing means including a sealing ring attached to one of said annularsupport portions and having at least one circumferential annular groove,and at least one stack of annular laminations attached to the other ofsaid annular support portions and located in said annular groove, saidlaminations having planar annular lateral surfaces abutting each other.2. Sealing arrangement as claimed in claim 1 comprising lubricatingmeans on one of said first and second means opening into said storagechamber for supplying the lubricating substance into the same. 3.Sealing arrangement as claimed in claim 1 wherein said laminationsconsist of hardened steel.
 4. Sealing arrangement as claimed in claim 1wherein said laminations have slits.
 5. Sealing arrangement as claimedin claim 1 wherein said sealing rings consist of a material insulatingagainst the flow of electric and heat currents.
 6. Sealing arrangementas claimed in claim 1 wherein said field generating first means isstationary, and said Eddy current developing second means is rotatableabout an axis; wherein said laminations engage and are attached to saidfirst annular support portion of said first stationary means; andwherein said sealing rings engage and are attached to said secondannular support portions of said second rotatable means.
 7. Sealingarrangement as claimed in claim 1 wherein each sealing ring has aplurality of parallel circumferential annular grooves; and wherein astack of annular laminations is located in each annular groove. 8.Sealing arrangement as claimed in claim 4 comprising a water repellinggrease in said annular grooves; and a ball bearing grease in saidstorage chamber.